User's Manual

LE920 Hardware User Guide

1vv0301026 Rev.0 - draft4 – 2013-05-

NOTE:

To check if the LE920 has powered on, the hardware line PWRMON must be monitored.

When PWRMON goes high, the module has powered on.

NOTE:

Do not use any pull up resistor on the ON# line, it is internally pulled up. Using pull up

resistor may bring to latch up problems on the LE920 power regulator and improper power

on/off of the module. The line ON# must be connected only in open collector configuration.

NOTE:

In this document all the lines are inverted. Active low signals are labeled with a name that

ends with "#" or with a bar over the name.

NOTE:

In order to avoid a back powering effect it is recommended to avoid having any HIGH logic

level signal applied to the digital pins of the module when is powered OFF or during an

ON/OFF transition.

For example:

1- Let us assume you need to drive the ON# pad with a totem pole output of a +1.8/5 V

microcontroller (uP_OUT1):